The present invention relates to a self-expanding vascular prosthesis for implantation in a blood vessel of a patient, with a vascular prosthesis trunk having a hollow-cylindrical main body and also a first and a second opening, and with at least two vascular prosthesis side branches branching off from the vascular prosthesis trunk.
It is generally known for intraluminal vascular prostheses or implants, also referred to as endovascular stents or stent grafts, to be used for treating weakened, damaged or torn vessels or aneurysms. For this purpose, a vascular implant or stent graft is released at the diseased or damaged site of the vessel and restores the functionality of the original vessel or supports the still existing integrity of the vessel.
An aneurysm is understood here as a widening or bulging of an arterial blood vessel as a consequence of congenital or acquired lesions of the wall. The bulge in this case can affect the vessel wall as a whole or, in what is called a false aneurysm or dissection, blood flows from the lumen of the vessel in between the layers of the vessel wall and tears these apart from one another. Non-treatment of an aneurysm may lead to a rupture of the artery in advanced stages, after which the patient suffers internal bleeding. The cause of a thoracic and thoraco-abdominal aortic aneurysm may be arteriosclerosis, high blood pressure and inflammation processes of the vessel wall. Injuries of the thorax due to serious accidents may also lead to acute or chronic aortic aneurysm.
The self-expanding vascular prostheses used for the treatment of aneurysms generally consist of a hollow-cylindrical metal frame or framework, of which the surface is covered by a textile or polymer film, such that a hollow-cylindrical body is obtained. For implantation, the vascular implant is radially compressed, such that its cross-sectional area is greatly reduced. With the aid of an insertion system, the vascular implant is then brought into the region of the aneurysm, where it is released. By virtue of the resilience of the metal frame or framework, the vascular implant expands again to its original shape and in so doing stretches its surface, which lodges inside the blood vessel proximally and distally in relation to the aneurysm. In this way, the blood now flows through the vascular implant, and further loading of the bulge is prevented.
The metal frame of such vascular implants generally consists, for example, of a wire mesh or of so-called stent springs, which are arranged one behind the other, extend in a meandering formation and, if appropriate, are connected to one another by connecting struts made of wire, or which are merely connected to one another via the material of the implant. The wire mesh or the stent springs are usually made of a shape-memory material, generally of Nitinol, as a result of which, after insertion into a vessel for release, the stent springs return to the expanded state and thus “open up” the vascular implant.
Aneurysms often occur in the region of the abdominal aorta (Aorta abdominalis) or thoracic aorta (Aorta thoracica), it being possible for a thoracic aneurysm to occur in what is called the ascending branch of the aorta (Aorta ascendens), in the aortic arch and/or in the descending branch of the aorta.
In the case of thoraco-abdominal aortic aneurysms, the aneurysm does not just remain confined to a limited part of the principal artery but is located both in the chest cavity, that is to say the thorax, and in the abdominal cavity (abdomen).
A thoraco-abdominal aortic aneurysm is a very complex clinical picture and is difficult to treat. Before the aortic stent became established, it was almost always necessary to open both the thorax and the abdominal cavity. It is nowadays alternatively possible, in the context of hybrid operations, for opening of the abdominal cavity to be performed in combination with an aortic stent, or for total endovascular treatment of thoraco-abdominal aortic aneurysms to be performed.
In the case of thoraco-abdominal aortic aneurysms, the situation is almost always made more difficult by the fact that arteries of all the major organs (arteries of the intestines, celiac trunk, renal arteries) are affected during the repair work and have to be reconstructed in some form or another. Treatment of a thoraco-abdominal aneurysm is therefore difficult, involves complications, and is often carried out by specialist centers.
The vascular prostheses used in the treatment have to meet many requirements, in particular with regard to the size, length and morphology of the aneurysm and native aorta to be bridged. The permeability of the segmental arteries in this region, the coexistence of other aneurysms, and the diameter of the iliac and femoral vessels also play an important role.
As before, there is therefore still a great need for stent/stent graft systems, or vascular prostheses, with the aid of which the intervention described above could be made easier and reduced in time.